Global Empirical Models of Wave Amplitudes and Normal Angles of Banded Plasmaspheric Hiss Obtained From Van Allen Probes Observations

Abstract

AbstractThe unique banded structure of plasmaspheric hiss with an upper band above ∼200 Hz and a lower band below ∼150 Hz has been recently reported. Based on observations from the twin Van Allen Probes from 15 September 2012 to 30 June 2019, we statistically investigate the global distributions of amplitude and power‐weighted wave normal angle (WNA) of banded hiss waves with respect to L, MLT, MLAT, and AE*. The results indicate that amplitudes of dayside banded hiss significantly depend on the substorm level (AE* index), while the variation of WNAs on the AE* index is slight. The WNAs of upper band hiss show a peak at L ∼ 3, while the WNAs of lower band hiss are relatively uniform at L < 4. The WNAs of both bands decrease with increasing L values at L > 4. We further develop the global empirical models of banded hiss wave amplitudes and WNAs to fit the statistical results, which show good agreement with satellite observations. These results can be essentially useful to evaluate the role of banded plasmaspheric hiss in the dynamic variations of Earth's radiation belt electrons.